Ok!, the two instances you were seeing were duplicate listings of the same instance. That bug was introduced a few days ago by some database optimizations, and is now fixed! Thanks for reporting it.
The 1.56 core-hours is mostly from inst_KGN6tZdFgoeL2C9KPKBsNA which has four physical cpus and has been running for almost an hour at this point.
Thanks so much for trying this out!!!